Anton’s Well Theater Company’s “Ages of the Moon” is a chamber play, in multiple senses of the word, even though it’s set on a porch.

A relatively recent work by the great playwright Sam Shepard, here presented in its Bay Area premiere, it’s very pared down at just an hour in length, with no break in the action and only two characters. The venue, at the Berkeley City Club, is the size of a large living room — a space so intimate and charming that right before the show starts, everyone watched director Robert Estes lean over to switch the house lights off.

This 2009 work is also a chamber play in that it distills many of the writer’s perennial themes, which are rendered more operatically in his most famous works — “Buried Child,” “Fool for Love,” “True West,” “A Lie of the Mind” — into something quieter, more still.

As in those seminal plays, the characters in “Ages of the Moon,” Ames (David Cramer) and Byron (Don Wood), aren’t sure how they met or how long they’ve been where they are, which is on Ames’ porch, below a finicky ceiling fan, so far out in the boonies that they might as well be on their own planet — the moon, in fact; they spend much of the play pondering its mysteries, debating whether they should stay up till dawn to catch a lunar eclipse.

They cast so much doubt on each other’s memories that even when they agree about something, they have to argue about it, asserting that no, they really do agree this time. And even then, the truth of their shared history feels unreliable and, more to the point, unimportant. It doesn’t really matter whether Byron came along on Ames’ honeymoon or really remembers a particular horse race; it doesn’t matter that even though they’re best friends, as they eventually admit, they haven’t seen each other in years and don’t know the central facts of each other’s lives.

What matters is the space each occupies in the other’s consciousness, the mythology they’ve constructed around their friendship, the way each holds himself superior to the other, affection morphing into resentment and rage, triggered by a single deadly phrase.

On the surface, “Ages of the Moon” consists of little more than two older guys shooting the breeze and drinking bourbon, but Estes and his actors mine riches from silences that seem to get almost as much air time as the dialogue — almost as if Shepard were trying his hand at a Beckett play.

The gulf of quiet that opens the show is especially revelatory. Cramer and Wood stare out, eyes blank, then quizzical, with a flicker or two of stronger feeling. Is it discomfort? Frustration? You keep thinking one or the other is taking a breath to speak, but if that’s the case, the impulse gets aborted, over and over — a dynamic that persists through the play, keeping the tension springy even as the dialogue is deceptively banal.

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As Byron, Wood gives a marvelously restrained performance, keeping his shifts in expression and intonation slight, which is perfect for the venue and which expertly communicates Byron’s stoicism, a product both of his generation and the way he deals with his own particular tragedy. The pair often take on the roles of a classic comic duo, and playing the duller member, Wood makes, again and again, a rich journey from silent puzzlement to proud ignorance.

It’s hard not to wish Cramer, always a skilled performer, were a bit less showy with Ames’ wild tangents and mercurial temperament, but he’s magical when Ames truly cares about something — data in an almanac, his friend’s well-being. Those moments are especially wonderful because of their rarity in Shepard’s canon; on the whole, his characters can’t, even for an instant, conceive of a world outside their own heads. When Cramer makes that trespass, the inevitable return to psychological isolation is all the more tragic.